I have an existing app where I have implemented FlipCard animation like below using Objectanimator in XML. If I click on a card it flips horizontally. But now I want to migrate it to jetpack compose. So is it possible to make flip card animation in jetpack compose?
Update
Finally, I have ended up with this. Though I don't know if it is the right way or not but I got exactly what I wanted. If there is any better alternative you can suggest. Thank you.
Method 1: Using animate*AsState
@Composable
fun FlipCard() {
var rotated by remember { mutableStateOf(false) }
val rotation by animateFloatAsState(
targetValue = if (rotated) 180f else 0f,
animationSpec = tween(500)
)
val animateFront by animateFloatAsState(
targetValue = if (!rotated) 1f else 0f,
animationSpec = tween(500)
)
val animateBack by animateFloatAsState(
targetValue = if (rotated) 1f else 0f,
animationSpec = tween(500)
)
val animateColor by animateColorAsState(
targetValue = if (rotated) Color.Red else Color.Blue,
animationSpec = tween(500)
)
Box(
Modifier.fillMaxSize(),
contentAlignment = Alignment.Center
) {
Card(
Modifier
.fillMaxSize(.5f)
.graphicsLayer {
rotationY = rotation
cameraDistance = 8 * density
}
.clickable {
rotated = !rotated
},
backgroundColor = animateColor
)
{
Column(
Modifier.fillMaxSize(),
horizontalAlignment = Alignment.CenterHorizontally,
verticalArrangement = Arrangement.Center
) {
Text(text = if (rotated) "Back" else "Front",
modifier = Modifier
.graphicsLayer {
alpha = if (rotated) animateBack else animateFront
rotationY = rotation
})
}
}
}
}
Method 2: Encapsulate a Transition and make it reusable. You will get the same output as method 1. But it is reusable and for the complex case.
enum class BoxState { Front, Back }
@Composable
fun AnimatingBox(
rotated: Boolean,
onRotate: (Boolean) -> Unit
) {
val transitionData = updateTransitionData(
if (rotated) BoxState.Back else BoxState.Front
)
Card(
Modifier
.fillMaxSize(.5f)
.graphicsLayer {
rotationY = transitionData.rotation
cameraDistance = 8 * density
}
.clickable { onRotate(!rotated) },
backgroundColor = transitionData.color
)
{
Column(
Modifier.fillMaxSize(),
horizontalAlignment = Alignment.CenterHorizontally,
verticalArrangement = Arrangement.Center
) {
Text(text = if (rotated) "Back" else "Front",
modifier = Modifier
.graphicsLayer {
alpha =
if (rotated) transitionData.animateBack else transitionData.animateFront
rotationY = transitionData.rotation
})
}
}
}
private class TransitionData(
color: State<Color>,
rotation: State<Float>,
animateFront: State<Float>,
animateBack: State<Float>
) {
val color by color
val rotation by rotation
val animateFront by animateFront
val animateBack by animateBack
}
@Composable
private fun updateTransitionData(boxState: BoxState): TransitionData {
val transition = updateTransition(boxState, label = "")
val color = transition.animateColor(
transitionSpec = {
tween(500)
},
label = ""
) { state ->
when (state) {
BoxState.Front -> Color.Blue
BoxState.Back -> Color.Red
}
}
val rotation = transition.animateFloat(
transitionSpec = {
tween(500)
},
label = ""
) { state ->
when (state) {
BoxState.Front -> 0f
BoxState.Back -> 180f
}
}
val animateFront = transition.animateFloat(
transitionSpec = {
tween(500)
},
label = ""
) { state ->
when (state) {
BoxState.Front -> 1f
BoxState.Back -> 0f
}
}
val animateBack = transition.animateFloat(
transitionSpec = {
tween(500)
},
label = ""
) { state ->
when (state) {
BoxState.Front -> 0f
BoxState.Back -> 1f
}
}
return remember(transition) { TransitionData(color, rotation, animateFront, animateBack) }
}
Output
We can make the Column scrollable by using the verticalScroll() modifier.
A LazyColumn is a vertically scrolling list that only composes and lays out the currently visible items. It's similar to a Recyclerview in the classic Android View system.
mutableStateOf creates an observable MutableState<T> , which is an observable type integrated with the compose runtime. Any changes to value will schedule recomposition of any composable functions that read value . In the case of ExpandingCard , whenever expanded changes, it causes ExpandingCard to be recomposed.
A Scaffold is a layout which implements the basic material design layout structure. You can add things like a TopBar, BottomBar, FAB or a Drawer.
setContent {
ComposeAnimationTheme {
Surface(color = MaterialTheme.colors.background) {
var state by remember {
mutableStateOf(CardFace.Front)
}
FlipCard(
cardFace = state,
onClick = {
state = it.next
},
axis = RotationAxis.AxisY,
back = {
Text(text = "Front", Modifier
.fillMaxSize()
.background(Color.Red))
},
front = {
Text(text = "Back", Modifier
.fillMaxSize()
.background(Color.Green))
}
)
}
}
}
enum class CardFace(val angle: Float) {
Front(0f) {
override val next: CardFace
get() = Back
},
Back(180f) {
override val next: CardFace
get() = Front
};
abstract val next: CardFace
}
enum class RotationAxis {
AxisX,
AxisY,
}
@ExperimentalMaterialApi
@Composable
fun FlipCard(
cardFace: CardFace,
onClick: (CardFace) -> Unit,
modifier: Modifier = Modifier,
axis: RotationAxis = RotationAxis.AxisY,
back: @Composable () -> Unit = {},
front: @Composable () -> Unit = {},
) {
val rotation = animateFloatAsState(
targetValue = cardFace.angle,
animationSpec = tween(
durationMillis = 400,
easing = FastOutSlowInEasing,
)
)
Card(
onClick = { onClick(cardFace) },
modifier = modifier
.graphicsLayer {
if (axis == RotationAxis.AxisX) {
rotationX = rotation.value
} else {
rotationY = rotation.value
}
cameraDistance = 12f * density
},
) {
if (rotation.value <= 90f) {
Box(
Modifier.fillMaxSize()
) {
front()
}
} else {
Box(
Modifier
.fillMaxSize()
.graphicsLayer {
if (axis == RotationAxis.AxisX) {
rotationX = 180f
} else {
rotationY = 180f
}
},
) {
back()
}
}
}
}
Check this article. https://fvilarino.medium.com/creating-a-rotating-card-in-jetpack-compose-ba94c7dd76fb.
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